Unable to add SDE featureclass to map using arcobjects

Question

I am currently in the process of converting our VBA apps to .net (C#) using Visual Studio 2010 and ArcGIS 10.1.

On my current project, I want to add a layer to the map from SDE.

I have the following code...

public void AddSDELayer(string server, string featureClassName)
{
    //create feature layer
    IFeatureLayer featureLayer = new FeatureLayer();

    //Create a workspace factory
    IWorkspaceFactory sdeWSFactory = new SdeWorkspaceFactory();

    //Create the property connections
    IPropertySet connectionProperties = new PropertySetClass();

    connectionProperties.SetProperty("SERVER", server);
    connectionProperties.SetProperty("INSTANCE", "5159");
    connectionProperties.SetProperty("USER", "anyone");
    connectionProperties.SetProperty("PASSWORD", "anyone");
    connectionProperties.SetProperty("VERSION", "SDE.DEFAULT");

    // create a workspace
    IWorkspace WS = sdeWSFactory.Open(connectionProperties, 0);

    //create featureworkspace
    IFeatureWorkspace featWS = WS as IFeatureWorkspace;

    //create feature class
    IFeatureClass featureClass;

    //Open the feature class
    featureClass = featWS.OpenFeatureClass(featureClassName);

    //set the feature layer to the featureclass
    featureLayer.FeatureClass = featureClass;
    featureLayer.Name = featureClass.AliasName;

    //Add the layer to the map
    map.AddLayer(featureLayer);

    MessageBox.Show(featureLayer.Name + " Added to map");
}

However when it gets to the following line

//Open the feature class
featureClass = featWS.OpenFeatureClass(featureClassName);

I get the following error in VS.

    DBMS table not found [ORA-00942: table or view does not exist
] [SY_DES_HM.Carriageway][STATE_ID = 596]

I've tried it with various layers that do exist, but the VS still doesn't like it, where am i going wrong?

Thanks